In general, a nitride semiconductor material including a group V source such as nitrogen (N) and a group III source such as gallium (Ga), aluminum (Al), or indium (In) has excellent thermal stability and a direct transition type energy band structure and thus is widely used as a material for a nitride-based semiconductor device such as a nitride-based semiconductor light emitting device in an ultraviolet light region and a solar cell.
The nitride-based material has a wide energy band gap of 0.7 eV to 6.2 eV, and thus is widely used as a material for a solar cell device due to the characteristics matching with the solar spectrum region. In particular, ultraviolet light emitting devices are used in various industrial fields such as a curing apparatus, a medical analyzer, a therapeutic apparatus, and a sterilizing, water purification, and purification system and is attracting attention as a usable material for general illumination as a semiconductor lighting source in the future.